She's probably using the vibrator so much because she's finding the 8 months difficult too, but has a problem with intimacy with you that isn't so easily solved. It's something you'll have to work at together or things will just get worse. Have you considered couples counseling?

Take it from a woman who also uses her vibrator almost every night. my husband and I have been in a four month dry spell now but it's him who is having problems not me. You really need to talk to her and figure out what's going on!!!

I don't have sex with my husband either, we have had sex once in 2 years, but I still use my vibrator. Penatrative sex may be painful for her. Open up to her and tell her how your uncomfortable with this and why, and ask her why she does it. You may be surprised at her answer.